High-power ruby laser with a stimulated Brillouin scattering mirror for generation of a high-temperature plasma

Wavefront reversal as a result of stimulated Brillouin scattering was used in a multistage ruby laser to improve the output radiation parameters. The divergence was reduced by more than an order of magnitude (to ~10^–4 rad) and the beam was focused down to a spot of ~100 μ size. A plasma with a temperature of ~200 eV and a density of ~10^–19 cm^–3 was generated. Spectra of H- and He-like fluorine ions were recorded in the wavelength range 15–17 Å. The coefficient representing conversion of laser radiation into x rays was ~5×10^–4. The use of wavefront reversal by stimulated Brillouin scattering and large-diameter (~40 mm) ruby rods should make it possible to increase considerably the power density of the heating radiation and to study the physics of heating of dense plasmas at short wavelengths.